Several conventional shock force indicating devices are known and utilized in the shipping and retail industries. These devices, however, do not visually show the extent of shock or force exerted on an article, such as a package or product, during shipping or handling of the article. Many such devices merely inform the user that the package or product has received a shock force that is over a specific, predetermined threshold. For example, one such device has a tiny liquid-filled glass tube housed in a self-adhesive label. If the device receives a shock beyond a predetermined threshold, the liquid in the tube changes from clear to bright red. However, the device is incapable of measuring the extent of shock to the package or product.
Additionally, U.S. Pat. No. 4,361,106, issued to Eklof, discloses a non-resettable shock force indicating device. The device has a circular bottom plate having a flange around its edge. There is a circular top section that is spaced apart from the inner surface of the circular plate and attached to the free edge portion of the flange. A top portion has a dome portion with a central axis and a peripheral side wall portion. The dome portion forms a chamber. The chamber is confined by a spring plate acting perpendicular to its extension. A central support column is directed perpendicular to the plate. The free end of the support column is cupular and provides a guiding support for a ball abutting the inner surface of the enlargement. The plate has openings such that spoke-like arms extend to the support column thereby rendering the plate spring-active in its perpendicular direction adjacent to the column. The cupular end presses against the ball which in turn presses against the inner surface of the dome portion. If the device is subjected to shock force greater than a predetermined threshold, the ball is dislodged from its normal position on the column. The column is displaced towards the upper inner surface of the dome portion by influence of the spring plate. The column serves as a blocking means for the ball to be returned to its normal position. While the device may indicate that a product has received a shock force over a predetermined threshold, the device is incapable of visually identifying the extent of shock to an article.
Another such conventional shock force indicating device comprises two sets of spring loaded steels balls disposed within a rugged transparent housing. The springs are calibrated to withstand forces up to the grating of the unit. If impacts greater than the rated value are imposed, at least one set of balls will be dislodged and dropped into a transparent zone for visual identification. While the device may also indicate that a product has received a shock force over a predetermined threshold, the device is incapable of measuring the extent of shock to the package or product.
Furthermore, U.S. Pat. No. 5,269,252, issued to Nagai, discloses a shock sensor which is able to detect an externally applied acceleration and which is designed to prevent the indicating means from reversing direction when a force in the opposite direction of detection is applied. The device may be affixed to an object by a screw. The device has an upper supporting member provided with a weight and a lower supporting member provided with a visible indicating plate. The upper and lower supporting members move independently of one another and are supported by a U-shaped fixing member. There is a V-shaped groove on a side face of the fixing member. The supporting members are designed to be in a higher position than the V-shaped groove such that a spring is bent upward into an arc-like shape. When the device is subjected to a downward G force greater than a predetermined value, the spring buckles from the upward arc-like shape to a downward arc-like shape. The ends of the supporting members also move downward and are maintained in the downward position by a downward elastic pressing force generated by the spring portion. In this position, the brightly colored indicating plate of the lower supporting member is visible through a transparent window. The indicating plate allows an individual to confirm that the product has been subjected to a force greater than a predetermined value. However, the device does not allow someone to visually confirm to what extent a package or product has been subjected to a force or shock.
Other conventional shock force indicating devices are capable of informing an individual of the extent of shock, however, they require one to download such information from the device and therefore, the extent of shock information is not readily ascertainable upon visual inspection. Therefore, an individual receiving a package at his home could not visually inspect the package and immediately make a decision to refuse or accept the package based on the device. For example, U.S. Pat. No. 5,982,285, issued to Bueche et al, discloses a shock force indicating device having a signal processing circuit disposed within a housing. The housing has side walls, a removable end wall, and a connection face. A plurality of screws couple the end wall with a side wall. An individual may access the circuit by removing the screws. The connection face provides a connection to an external sensor assembly and to a personal computer assembly. The external sensor assembly has sensor modules that are connected to respective mounting blocks. The mounting blocks are configured to stack one atop the other with the block positioned against the connection face of housing. The device is capable of monitoring impact via an accelerometer, and also temperature and humidity with alternate sensors. The sensor and time data must be downloaded onto a PC to determine the extent of shock on an article. Such information is not available upon visual inspection and the process for obtaining such data is very time consuming and often impractical for typical receiving situations.
Furthermore, U.S. Pat. No. 5,936,523, issued to West, discloses a device having an acceleration sensor which is capable of sending an output to a reporting unit and decoder. The reporting unit monitors a signal from the acceleration sensor for evidence of excessive acceleration from the mishandling of an article. The device is also incapable of displaying data as to the extent of shock to an article by simple visual inspection and requires time-consuming manipulation of the device.
Therefore, it would be advantageous to provide a shock force indicating device capable of measuring and displaying the extent of a shock force to an article.